Preface for the first edition

This book offers an overview of various sensors and sensor systems as required and applied in mechatronics. Emphasis lies on the physical background of the operating principles, illustrated with examples of commercially available sensors and of recent and future developments. The work is adapted from a course book on sensors for mechatronic systems, used by students in Electrical and Mechanical Engineering of the University of Twente, The Netherlands. It tries to give an answer to the following questions:

A mechatronic system uses information from its internal state as well as from its environment, in order to operate properly. This information is obtained using sensors. In many situations turnkey sensing systems are available on the sensor market. For many other, newly defined applications, such a solution is not feasible, and a sensing system should be assembled from obtainable or specifically designed subsystems. This book offers a help in achieving the best solution to various kinds of sensor problems encountered in mechatronics, by reviewing the major types of transducers, a characterization of the state-of-the-art in sensing technology and a view on current sensor research.

Sensors operate in at least two different physical domains. Therefore, the first chapter discusses general aspects of sensors, with a special section on quantities, notations, and relations concerning these various domains. Moreover, it includes a section devoted to sensor errors and error minimization that apply to most of the sensors discussed in this book. Each of the subsequent chapters deals with one class of sensors, pursuing a classification according to physical principles rather than to measurands. These categories are resistive, capacitive, inductive and magnetic, optical, piezoelectric, and acoustic sensors. Each of these chapters starts with a brief introduction to the physical background, from which follow the basic properties and limitations of such sensors. In subsequent sections, different types and constructions are given, together with the typical specifications and maximal ratings for devices available on the sensor market. For each category of sensors, a number of applications are given. Where appropriate, a section is added on the interfacing of the sensor.

This book is written for people involved in designing mechatronic systems and robots but who are not specialist in sensor technology. However, the reader is assumed to have some background knowledge on physics and electronics. Nevertheless, some basic principles are briefly reviewed as a recollection, to facilitate reading. Moreover, readers who are not familiar with certain parts of physics are briefly introduced into the subject. Finally, each chapter ends with a section on literature (books and journal papers) as a reference for readers where to find further information on the topics discussed in that chapter. At the back of the book, appendices are found providing elementary electronic interface circuits, together with expressions describing their performance.

The author welcomes all kinds of comments and suggestions that will result in an increased quality of the work.